Although rescue dogs were first trained as paratroopers in 1944, the first military dog to skydive from an altitude of 12,500 feet was Sgt. Maj. Fosco in 2009. He jumped in tandem with U.S. Army 1st Sgt. Chris Lalonde.

Clearly, that's an extreme case of a downward-facing dog.

For a less daredevil rendition, we suggest you try the yoga pose instead. Downward Facing Dog is one of the first postures you'll learn when starting yoga. And the pose morphs easily into Upward Facing Dog.

It's as uplifting as this ancient practice is for sagging muscles and tired spirits.

In fact, a recent Swedish study found that doing yoga once a week for an hour can be a life-changing, health-boosting experience, especially for people with high anxiety.

The researchers looked at a group of people diagnosed with paroxysmal atrial fibrillation (a type that starts and suddenly stops; now, there's some high anxiety) to see how yoga might improve their health.

Half of the people in the study received standard treatment, and half received standard treatment, plus yoga. After three months the researchers say the yoga group saw a drop in blood pressure, a slowing of heart rates, and overall better mental health.